Large Dewflower is a perennial herb, 30-60 cm. Flowers opening in late afternoon. Petals 3, equal, obovate, about1 cm. Stamens: 2 upper, fertile and curved downwards, the third sterile; filaments with long purple, beaded hairs. Staminodes 3 with glabrous filaments, the empty anthers yellow and 3-lobed. Capsule oblong-spherical, c.6 mm. Seeds oblong-spherical, 1.5 mm, the transverse ribs tuberculate, reticulate.